Anatomy of an Active Submarine Volcano
Downloaded from geology.gsapubs.org on July 28, 2014 Anatomy of an active submarine volcano A.F. Arnulf1, A.J. Harding1, G.M. Kent2, S.M. Carbotte3, J.P. Canales4, and M.R. Nedimović3,5 1Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California–San Diego, La Jolla, California 92093, USA 2Nevada Seismological Laboratory, 0174, University of Nevada–Reno, Reno, Nevada 89557, USA 3Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA 4Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02540, USA 5Department of Earth Sciences, Dalhousie University, Halifax, Nova Scotia B3H4J1, Canada ABSTRACT To date, seismic experiments have been one Most of the magma erupted at mid-ocean ridges is stored in a mid-crustal melt lens that lies of the keys in our understanding of the inter- at the boundary between sheeted dikes and gabbros. Nevertheless, images of the magma path- nal structure of volcanic systems (Okubo et al., ways linking this melt lens to the overlying eruption site have remained elusive. Here, we have 1997; Kent et al., 2000; Zandomeneghi et al., used seismic methods to image the thickest magma reservoir observed beneath any spreading 2009; Paulatto et al., 2012). However, most ex- center to date, which is principally attributed to the juxtaposition of the Juan de Fuca Ridge periments, especially subaerial-based ones, are with the Cobb hotspot (northwestern USA). Our results reveal a complex melt body, which restricted to refraction geometries with limited is ~14 km long, 3 km wide, and up to 1 km thick, beneath the summit caldera.
[Show full text]